Cheryl, TVo, Keita, Jenne

Summary: The IMC is aligned and flashing.  The IMC REFL path on IOT2 is aligned.  The IMC trans path that comes from the transmission through IM1 is coming out of the viewport and light pipe, but not hitting the top periscope mirror by about 2 inches to the right as you're looking at the viewport from the IOT2 door (this is consistent with our having moved this beam farther from clipping on the edge of the viewport as noted in alog 39804). 

To do this:

• We basically followed Cheryl's plan of using the input PZT to align the leakage beam onto MC2 Trans, as a proxy for centering on MC2, while MC3 was misaligned so we weren't getting flashes.  To really see anything, we had to increase the whitening gain on MC2 Trans (H1:IMC-MC2_TRANS_WHITEN_GAIN) from its nominal of 36dB to the max of 45dB, and reset the dark offsets of each segment while the PSL shutter was closed.  We also increased the PSL power injected into the vacuum to ~4W. N.b. that the monitor PD for the amount of light injected seems to be not well aligned, so we just used whatever was in the rotation stage's calibration and requested 4W, but we didn't have an independent monitor of the actual power injected. 
• We then used MC2 to center the beam on the aperture of the baffle that is behind IM1, under the assumption that the baffle was well placed, so it's a proxy for getting the beam where we want on IM1.  Cheryl has a camera and TV set up on the floor for this purpose, as she described in alog 39955.
• MC1 and MC3 were tweaked a bit to maximize the flashes on MC2 Trans, but they didn't need much. 
• (Note to Cheryl: we touched the PZT and MC2 sliders again after you left, so what's in there now are our latest good values.  MC1 and MC3 didn't need any more touching)
• Once MC1 was set, we aligned the beam onto the MC REFL RFPD, IMC WFS A, IMC WFS B, and the IMC Refl camera. 

We're not yet really seeing any signal on H1:IMC-I_OUT, but the LSC computer seems to maybe be bad again, so I'll leave locking as an exercise for tomorrow.  No checking of analog electronics has been done tonight (by me, at least).

Still to do: We need to move the IMC Trans periscope on IOT2 a few inches toward the PSL enclosure, and will have to redo (move) that whole optical path to match.  Also being left as an exercise for the morning.  Until this is done, we won't have the nice trans camera to see the shapes of our flashes.  However, just looking on a card, we're mostly flashing 00, 01, and 10 modes, so everything should be pretty smooth going tomorrow.